• IEIE Transactions on Smart Processing and Computing
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• v.5 no.1
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• pp.5-9
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• 2016

The modulation bandwidth of a reflective semiconductor optical amplifier (RSOA) is limited by carrier lifetime. Therefore, it is hard to directly modulate an RSOA with high-speed electrical signals. We theorize that an optical filter can act as an optical equalizer, compensating for the narrow bandwidth limitation imposed by the RSOA. By modeling a time-varying RSOA with a modified transfer matrix method (TMM), we simulated 25 Gbps operation of an RSOA with optical filtering effects. We investigated the impact of detuning the center wavelength of the optical filter on the modulation of an RSOA. The numerical results show that it is possible to modulate an RSOA with an optical filtering effect at 25 Gbps without electronic equalization or digital signal processing.

• Current Optics and Photonics
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• v.2 no.6
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• pp.563-567
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• 2018

We propose and experimentally demonstrate a simple tunable photonic microwave band-pass filter with high resolution using a reflective semiconductor optical amplifier (RSOA) and an optical time-delay line. The RSOA is used as a gain medium for generating cross-gain modulation (XGM) effect as well as an optical source. The optical source provides narrow spectral width by self-injection locking the RSOA in conjunction with a partial reflection filter with specific center wavelength. Then, when the RSOA is operated in the saturation region and the modulated recursive signal is injected into the RSOA, the recursive signal is inversely copied to the injection locked optical source due to the XGM effect. Also, the tunability of the passband of the proposed microwave filter is shown by controlling an optical time-delay line in a recursive loop.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.5
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• pp.418-424
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• 2014

We propose and experimentally demonstrate a photonic microwave notch filter with a negative coefficient. The negative coefficient is obtained by using cross gain modulation (XGM) in a reflective semiconductor optical amplifier (RSOA). When the RSOA is operated in saturated region, the signal carried on the pump wavelength is inversely copied to the probe wavelength by the XGM effect, showing a negative coefficient. Time delay between pump signal and probe signal is provided by single mode fiber (SMF) with wavelength dependent time delay. The proposed microwave notch filter shows notch dips of more than 35.1 dB and free spectral range (FSR) of about 380.6 MHz.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.4 no.1
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• pp.15-21
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• 2005

One of the core technology in WDM-PON system is a generation and modulation technique of the optical source in Optical Network Unit (ONU). In this paper, we propose a reflective semiconductor optical amplifier (RSOA) as a modulator in WDM-PON system. Its performance is analyzed by simulation and actual experimentation. Using RSOA in WDM-PON system as a modulator, it obtains higher gain compared to the conventional SOA due to the double pass gain effect. Furthermore RSOA can provide high gain with comparatively low input power. This is very helpful when we set up the actually system because using lower input power, it can reduce the load of the driving circuit which makes very economical module structure. Therefore, when RSOA is used as a modulator, not only it gives noise suppression effect, but also provides certain amount of gain as well. In addition, comparing with conventional SOA which gives fairly large insertion loss, RSOA can provides more important merits.

• Korean Journal of Optics and Photonics
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• v.23 no.6
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• pp.264-268
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• 2012

In this paper, we propose a new method for broadcasting in a WDM-PON system which has the merits of a simple and cost effective structure. It can be constructed using only an ASE (Amplified Spontaneous Emission) light source and a PI-RSOA (Polarization Independent - Reflective Semiconductor Optical Amplifier). Error-free broadcast signal transmission over 30 Km for 24 channels at 1.25 Gb/s has been successfully demonstrated.

• ETRI Journal
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• v.32 no.2
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• pp.248-254
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• 2010

We demonstrate a linear bus wavelength-reused gigabit wavelength-division multiplexing passive optical network (WDM-PON) with multiple optical add-drop nodes. A commercially available reflective semiconductor optical amplifier-based WDM-PON has a sufficient power budget to provide multiple optical add/drop nodes in 16 WDM channels. Sixteen 1.25 Gb/s WDM channels are successfully transmitted over 20 km of single-mode fiber with four optical add/drop multiplexers, even with 32 dB reflection and chromatic dispersion in the link.

• Current Optics and Photonics
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• v.2 no.1
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• pp.27-33
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• 2018

We report the physical implementation of a tunable photonic microwave delay line filter based on injection locking of a single Fabry-Perot laser diode (FP-LD) to a reflective semiconductor optical amplifier (RSOA). The laser generates equally spaced multiple wavelengths and a single tapped-delay line can be obtained with a dispersive single mode fiber. The filter frequency response depends on the wavelength spacing and can be tuned by the temperature of the FP-LD varying lasing wavelength. For amplitude control of the wavelengths, we use gain saturation of the RSOA and the offset between the peak wavelengths of the FP-LD and the RSOA to decrease the amplitude difference in the wavelengths. From the temperature change of total $15^{\circ}C$, the filter, consisting of four flat wavelengths and two wavelengths with slightly lower amplitudes on both sides, has shown tunability of about 390 MHz.

• Journal of the Optical Society of Korea
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• v.11 no.4
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• pp.158-161
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• 2007

We proposed a novel linearization technique for a DFB LD in the RoF link. The proposed scheme is based on the cross gain modulation(XGM) effect of a reflective semiconductor optical amplifier(RSOA) with light injection. We experimentally demonstrated and evaluated the enhanced CIR performance using the proposed linearization scheme.

• Journal of the Optical Society of Korea
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• v.12 no.4
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• pp.359-363
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• 2008

A novel WDM-PON system delivering bidirectional 1.25-Gbps data and broadcasting data is proposed. A subcarrier signal modulates optical carriers of a Fabry-Perot-laser-diode based broadband light source to broadcast to all users. Reflective semiconductor optical amplifiers are used as modulators for the baseband data at both the optical line terminal and the remote optical network unit for a channel. Bit error rate and error vector magnitude were measured to demonstrate the proposed scheme.

• Journal of the Optical Society of Korea
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• v.15 no.3
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• pp.222-226
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• 2011

We demonstrated the feasibility of an amplified wavelength-division multiplexed passive optical network (WDM-PON) architecture based on broadband light source (BLS) seeded optical sources and a novel bidirectional reach extender. Our bidirectional reach extender could provide an amplification of both downstream and upstream signals as well as a BLS output for the upstream WDM signal generation. An error-free 1.25 Gb/s signal transmission over a 100-km long single-mode fiber was achieved in a bidirectional WDM-PON using BLS seeded reflective semiconductor optical amplifier (RSOA) sources.